The present invention generally relates to enteral nutrition wherein fluid nutrients are administered to the human gastrointestinal tract through an enteral feeding tube and, in particular, to improvements to a device for relieving gastric pressure in neonatal and pediatric patients during enteral feeding.
Enteral nutrition is a form of hyperalimentation and metabolic support in which nutrient formulas or medicaments are delivered directly to the gastrointestinal tract, either the stomach or the duodenum. Nutrient administration is accomplished through use of an enteral feeding system generally comprising an enteral feeding container, usually a distensible bag suspended above patient level, joined to a length of flexible administration tubing. The proximal end of the administration tubing, which is joined to an outlet port in the enteral feeding bag, may include a drip chamber-tube clamp arrangement for determining flow rate. The distal end of the administration tubing carries a male luer adaptor for coupling with a female luer adaptor disposed on a distal end of an enteral feeding tube. U.S. Pat. No. 4,490,143 generally discloses the arrangement of elements utilized in an enteral feeding system. Intubation of the enteral feeding tube may be through naso-pharyngeal passage or through oral intubation. The flow rate of fluid nutrient through the enteral feeding tube is achieved through either gravity feed or use of an enteral feeding pump disposed at a generally intermediate position along the administration tubing.
During enteral feeding excessive gastric pressure may result through accumulation of gas or liquid resulting from stomach contractions, movement of the patient""s abdomen, crying or through normal formation of gas. Typically the body relieves such excess gastric pressure through expulsion of accumulated gas or liquid through a burping response. However, in a patient undergoing enteral feeding in which fluid nutrients are being continually fed to the gastrointestinal tract, upward expulsion of gastric reflux materials is highly undesirable. More importantly, reflux of gas or liquid through the enteral feeding tube cannot occur. Though gastric reflux pressure created by even limited episodes of stomach movement or crying may exceed several feet of water, such reflux pressure is inadequate to overcome the greater forward fluid pressure present within the enteral feeding tube. This greater fluid pressure is developed because the height of the column of fluid nutrient in the enteral feeding system stands well above the level of the patient""s stomach. Fluid pressure is further increased through the use of the enteral feeding pump. In addition, tube set clamps along the administration tubing also prevent reflux of excessive gastric gas or liquid through the enteral feeding tube.
Because gastric reflux pressure cannot overcome the greater forward fluid pressure within the enteral feeding tube, reflux materials are expelled upward from the stomach through the esophagus and are expressed out of the mouth, where the enteral feeding tube is orally intubated, or through the nasal passages, where naso-pharyngeal intubation has been utilized. In the latter, it is possible for the patient to inhale the reflux materials into the lungs with possible risk of aspiration pneumonia. The problem of relief of gastric reflux pressure is most accute in neonates, infants and small children in which gastric pressure may rapidly accumulate through periodic episodes of crying and because such patients have yet to develop control over the burping response as a means of gastric pressure relief. However, it is not unusual for adult patients undergoing enteral feeding to experience occasional difficulties with gastric reflux pressure relief.
Gastric pressure relief devices such as device 10 in FIG. 1 have been developed to permit relief of gastric reflux pressure through the enteral feeding tube to avoid uncontrolled upward expulsion of reflux materials through the burping response. Device 10 also prevents introduction of air into any portion of the enteral feeding system, particularly the enteral feeding tube. Further, because the fluid refluxed by a patient generally comprises the nutrient formula being administered to the patient, after device 10 relieves gastric reflux pressure, the refluxed fluid nutrient is returned to the enteral feeding tube for delivery to the patient. However, the quantity of refluxed fluid nutrient, particularly fluid which collects within tube line 18 is often unknown. This adversely impacts accurate enteral administration of fluid nutrient, particularly since a selected quantity of nutrient is administered over a given period of time. Hence, prior to the development of the improvements to device 10 as disclosed herein, a need existed for a gastric reflux pressure relief device which temporarily collects, accurately measures and returns refluxed nutrient formula to the enteral feeding tube.
According to the present invention improvements to a gastric reflux pressure relief device have been developed for in-line incorporation into an enteral feeding system. The pressure relief device is interposed between the distal end of an administration tubing and proximal end of the enteral feeding tube for capturing refluxed fluid.
The pressure relief device includes a selected length of pressure relief tubing having a fluid collection reservoir on a proximal end. A male luer adaptor is disposed at a distal end of the relief tubing for coupling with a female luer adaptor at a proximal end of an enteral feeding tube. Joined along a selected position on the relief tubing is a Y-connector for receiving the male luer adaptor commonly utilized on the distal end of enteral administration tubing. Hence, the relief tubing is in fluid communication with both a source of fluid nutrient and the enteral feeding tube. The Y-connector is interposed at a position about ⅔ of the length of the relief tubing so that the segment of tubing proximal to the Y-connector defines a pressure relief segment while the segment of the tubing distal to the Y-connector delivers fluid nutrient received from the administration tubing to the enteral feeding tubing. The reflux material collection reservoir, preferably a flexible plastic tail-feeding bag, is vented to the ambient atmosphere. Where reflux materials include gas, the gas is released from the present pressure relief apparatus through the vent. On the other hand, where the reflux materials include fluid, then the reservoir temporarily collects and retains the fluid before gradual return and delivery to the patient. Though the collection reservoir is vented to the ambient atmosphere, so long as the Y-connector is positioned at or below the patient""s stomach level, a standing column of fluid nutrient will be maintained above the Y-connector, thereby preventing suction of air into the enteral feeding system through the reservoir gas vent.
It has been found that because the reservoir has inner dimensions larger than the relief tubing, the reservoir best functions to receive and expel refluxed gas. Though the reservoir has volumetric markings, refluxed formula rarely enters the reservoir. Instead, formula most commonly is refluxed into the relief tubing above the Y-connector. As a result, the relief tubing may carry a meaningful quantity of formula, particularly, for neonatal patients. Hence, the relief device has been improved by providing the relief tubing with volumetric indicia or markings.
The present invention will be more fully described in the following detailed description with reference being made to the drawings and the Claims appended thereto.